It is colorless column crystal, odorless, slightly deliquescence. The relative density is 2.04 and melting point is 60℃. It is easily soluble in water but insoluble in ethanol. If heated below 100℃, it can dissolve in crystal water and convert to monohydrate salt. When heated to 100℃, it will lose crystal water and change to anhydrous substances, which will become sodium metaphosphate if continue to be heated.